Animal ingress/egress doors and openings are formed to allow the passage of one or more animals between partitioned spaces. As used herein, the term “pet” refers both to companion animals as well as working, livestock, zoo, or wild animals.
Pet openings are apparatuses that generally allow for the movement of animals between environments, such as between an indoor environment and the outdoors. Frequently, pet openings include a self-closing panel, such as a flap, that may be pushed open from either side by an animal. When the animal is indoors, it may exit by pushing its nose against the inner surface of a relatively free-swinging flap, causing the flap to swing outwards to allow the animal to pass its body between the out-swung flap and the lower edge of the door aperture. Similarly, an animal may enter a space by pushing its nose against the outer surface of the flap, causing the flap to swing inward and thus allowing the animal to pass between the in-swung flap and the lower edge of the door aperture.
The use of a pet door thus allows a pet to move back and forth between the inside of a residence, kennel, zoo enclosure, etc, and an outdoor space without intervention by the animal keeper or owner.
According to the prior art, a common theme has focused on improving weather-resistance of pet doors. Gribble U.S. Pat. No. 6,725,806, for example, discloses a “resiliently flexible seal” that is mounted around the pet door to prevent the intrusion of drafts. Gribble further discloses a latch for latching the U.S. Pat. No. 6,681,524 to Tillson discloses a “door within a door” that allows two-way access while creating seals between the doors and their respective frames that are secured by the weight of the door (and door plus frame) being supported at a non-vertical angle.
Other prior art has focused on improving the security of pet doors. For example, U.S. Pat. No. 6,691,463 to Richmond discloses a sliding kennel door apparatus that may be remotely raised to open by manual, electrical, hydraulic, or pneumatic means. Gillett, U.S. Pat. No. 6,560,926 discloses a pet door having an opening mechanism that includes a receiver and portable transmitter. Kenum, U.S. Pat. No. 6,433,692 discloses a signaling mechanism that allows a trained pet to “ring a doorbell” to request entry. Small, U.S. Pat. No. 6,297,739 discloses a rather complicated system that interrogates an identification device carried by authorized animals and unlocks the pet door in response to the presence of the authorized animal. This is combined with a weight sensor that discriminates between the weight of authorized and unauthorized animals Marsh et al., U.S. Pat. No. 6,385,909 discloses a rather simpler pet door that includes a sliding lock mechanism that allows the owner to determine whether or not to allow access. Brooks, U.S. Pat. No. 6,453,847 discloses an electro-magnetically actuated door that is released to open by a magnet carried by the authorized animal.
Still other pieces of prior art pertain to pet door security covers that may be installed to prevent intrusion by keeping a pet door closed.
Additionally, a certain amount of attention has been paid to creation of a pet door that may be installed in an existing opening, such as a window, without necessitating the substantially non-reversible cutting of an aperture. For example, U.S. Pat. No. 6,691,483 to Lethers discloses a panel that may be installed in an existing sliding glass door opening.
There remains a need to provide a simple apparatus that affords security while allowing operation of the pet door. There remains a need to provide an apparatus that affords a measure of weather protection while allowing operation of the pet door and without requiring tight seals that hinder motion of a pet door. There further remains a need for a simple apparatus that reduces or eliminates the entry of unwanted animals but without the need to train pets or otherwise provide expensive identification devices.